Blow Door Testing

A blower door test determines how much and where air is leaking out of your house.

A basic blower-door system includes three components: a calibrated fan, a door-panel system, and a manometer to measure pressure. The door panel system is mounted into one of the home entrances. The calibrated fan mounts into the door panel system. To conduct the test, the fan is turned on to pull air out of the house, lowering the air pressure inside. The manometer measures flow and pressure, which are used in a variety of calculations. As the home is air sealed, the flow of air measured by the manometer decreases, quantifying the reduction in air leakage.

Blower door tests are useful for weatherization projects and are required by the state in new home construction and most remodels.

As part of a home energy assessment, a blower door test represents an easy, cost-effective way to understand your home’s energy performance.

Step 1: The door frame is assembled and fit to the door.

Step 2: The frame cover is attached and the fan is inserted.

Step 3: The manometer is connected to record test results while the technician performs a walk through.